1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Mediatek Watchdog Driver
4 *
5 * Copyright (C) 2014 Matthias Brugger
6 *
7 * Matthias Brugger <matthias.bgg@gmail.com>
8 *
9 * Based on sunxi_wdt.c
10 */
11
12#include <dt-bindings/reset/mt2712-resets.h>
13#include <dt-bindings/reset/mediatek,mt6735-wdt.h>
14#include <dt-bindings/reset/mediatek,mt6795-resets.h>
15#include <dt-bindings/reset/mt7986-resets.h>
16#include <dt-bindings/reset/mt8183-resets.h>
17#include <dt-bindings/reset/mt8186-resets.h>
18#include <dt-bindings/reset/mt8188-resets.h>
19#include <dt-bindings/reset/mt8192-resets.h>
20#include <dt-bindings/reset/mt8195-resets.h>
21#include <linux/delay.h>
22#include <linux/err.h>
23#include <linux/init.h>
24#include <linux/io.h>
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/of.h>
29#include <linux/platform_device.h>
30#include <linux/reset-controller.h>
31#include <linux/types.h>
32#include <linux/watchdog.h>
33#include <linux/interrupt.h>
34
35#define WDT_MAX_TIMEOUT 31
36#define WDT_MIN_TIMEOUT 2
37#define WDT_LENGTH_TIMEOUT(n) ((n) << 5)
38
39#define WDT_LENGTH 0x04
40#define WDT_LENGTH_KEY 0x8
41
42#define WDT_RST 0x08
43#define WDT_RST_RELOAD 0x1971
44
45#define WDT_MODE 0x00
46#define WDT_MODE_EN (1 << 0)
47#define WDT_MODE_EXT_POL_LOW (0 << 1)
48#define WDT_MODE_EXT_POL_HIGH (1 << 1)
49#define WDT_MODE_EXRST_EN (1 << 2)
50#define WDT_MODE_IRQ_EN (1 << 3)
51#define WDT_MODE_AUTO_START (1 << 4)
52#define WDT_MODE_DUAL_EN (1 << 6)
53#define WDT_MODE_CNT_SEL (1 << 8)
54#define WDT_MODE_KEY 0x22000000
55
56#define WDT_SWRST 0x14
57#define WDT_SWRST_KEY 0x1209
58
59#define WDT_SWSYSRST 0x18U
60#define WDT_SWSYS_RST_KEY 0x88000000
61
62#define WDT_SWSYSRST_EN 0xfc
63
64#define DRV_NAME "mtk-wdt"
65#define DRV_VERSION "1.0"
66
67#define MT7988_TOPRGU_SW_RST_NUM 24
68
69static bool nowayout = WATCHDOG_NOWAYOUT;
70static unsigned int timeout;
71
72struct mtk_wdt_dev {
73 struct watchdog_device wdt_dev;
74 void __iomem *wdt_base;
75 spinlock_t lock; /* protects WDT_SWSYSRST reg */
76 struct reset_controller_dev rcdev;
77 bool disable_wdt_extrst;
78 bool reset_by_toprgu;
79 bool has_swsysrst_en;
80};
81
82struct mtk_wdt_data {
83 int toprgu_sw_rst_num;
84 bool has_swsysrst_en;
85};
86
87static const struct mtk_wdt_data mt2712_data = {
88 .toprgu_sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
89};
90
91static const struct mtk_wdt_data mt6735_data = {
92 .toprgu_sw_rst_num = MT6735_TOPRGU_RST_NUM,
93};
94
95static const struct mtk_wdt_data mt6795_data = {
96 .toprgu_sw_rst_num = MT6795_TOPRGU_SW_RST_NUM,
97};
98
99static const struct mtk_wdt_data mt7986_data = {
100 .toprgu_sw_rst_num = MT7986_TOPRGU_SW_RST_NUM,
101};
102
103static const struct mtk_wdt_data mt7988_data = {
104 .toprgu_sw_rst_num = MT7988_TOPRGU_SW_RST_NUM,
105 .has_swsysrst_en = true,
106};
107
108static const struct mtk_wdt_data mt8183_data = {
109 .toprgu_sw_rst_num = MT8183_TOPRGU_SW_RST_NUM,
110};
111
112static const struct mtk_wdt_data mt8186_data = {
113 .toprgu_sw_rst_num = MT8186_TOPRGU_SW_RST_NUM,
114};
115
116static const struct mtk_wdt_data mt8188_data = {
117 .toprgu_sw_rst_num = MT8188_TOPRGU_SW_RST_NUM,
118};
119
120static const struct mtk_wdt_data mt8192_data = {
121 .toprgu_sw_rst_num = MT8192_TOPRGU_SW_RST_NUM,
122};
123
124static const struct mtk_wdt_data mt8195_data = {
125 .toprgu_sw_rst_num = MT8195_TOPRGU_SW_RST_NUM,
126};
127
128/**
129 * toprgu_reset_sw_en_unlocked() - enable/disable software control for reset bit
130 * @data: Pointer to instance of driver data.
131 * @id: Bit number identifying the reset to be enabled or disabled.
132 * @enable: If true, enable software control for that bit, disable otherwise.
133 *
134 * Context: The caller must hold lock of struct mtk_wdt_dev.
135 */
136static void toprgu_reset_sw_en_unlocked(struct mtk_wdt_dev *data,
137 unsigned long id, bool enable)
138{
139 u32 tmp;
140
141 tmp = readl(addr: data->wdt_base + WDT_SWSYSRST_EN);
142 if (enable)
143 tmp |= BIT(id);
144 else
145 tmp &= ~BIT(id);
146
147 writel(val: tmp, addr: data->wdt_base + WDT_SWSYSRST_EN);
148}
149
150static int toprgu_reset_update(struct reset_controller_dev *rcdev,
151 unsigned long id, bool assert)
152{
153 unsigned int tmp;
154 unsigned long flags;
155 struct mtk_wdt_dev *data =
156 container_of(rcdev, struct mtk_wdt_dev, rcdev);
157
158 spin_lock_irqsave(&data->lock, flags);
159
160 if (assert && data->has_swsysrst_en)
161 toprgu_reset_sw_en_unlocked(data, id, enable: true);
162
163 tmp = readl(addr: data->wdt_base + WDT_SWSYSRST);
164 if (assert)
165 tmp |= BIT(id);
166 else
167 tmp &= ~BIT(id);
168 tmp |= WDT_SWSYS_RST_KEY;
169 writel(val: tmp, addr: data->wdt_base + WDT_SWSYSRST);
170
171 if (!assert && data->has_swsysrst_en)
172 toprgu_reset_sw_en_unlocked(data, id, enable: false);
173
174 spin_unlock_irqrestore(lock: &data->lock, flags);
175
176 return 0;
177}
178
179static int toprgu_reset_assert(struct reset_controller_dev *rcdev,
180 unsigned long id)
181{
182 return toprgu_reset_update(rcdev, id, assert: true);
183}
184
185static int toprgu_reset_deassert(struct reset_controller_dev *rcdev,
186 unsigned long id)
187{
188 return toprgu_reset_update(rcdev, id, assert: false);
189}
190
191static int toprgu_reset(struct reset_controller_dev *rcdev,
192 unsigned long id)
193{
194 int ret;
195
196 ret = toprgu_reset_assert(rcdev, id);
197 if (ret)
198 return ret;
199
200 return toprgu_reset_deassert(rcdev, id);
201}
202
203static const struct reset_control_ops toprgu_reset_ops = {
204 .assert = toprgu_reset_assert,
205 .deassert = toprgu_reset_deassert,
206 .reset = toprgu_reset,
207};
208
209static int toprgu_register_reset_controller(struct platform_device *pdev,
210 int rst_num)
211{
212 int ret;
213 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);
214
215 spin_lock_init(&mtk_wdt->lock);
216
217 mtk_wdt->rcdev.owner = THIS_MODULE;
218 mtk_wdt->rcdev.nr_resets = rst_num;
219 mtk_wdt->rcdev.ops = &toprgu_reset_ops;
220 mtk_wdt->rcdev.of_node = pdev->dev.of_node;
221 ret = devm_reset_controller_register(dev: &pdev->dev, rcdev: &mtk_wdt->rcdev);
222 if (ret != 0)
223 dev_err(&pdev->dev,
224 "couldn't register wdt reset controller: %d\n", ret);
225 return ret;
226}
227
228static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
229 unsigned long action, void *data)
230{
231 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd: wdt_dev);
232 void __iomem *wdt_base;
233 u32 reg;
234
235 wdt_base = mtk_wdt->wdt_base;
236
237 /* Enable reset in order to issue a system reset instead of an IRQ */
238 reg = readl(addr: wdt_base + WDT_MODE);
239 reg &= ~WDT_MODE_IRQ_EN;
240 writel(val: reg | WDT_MODE_KEY, addr: wdt_base + WDT_MODE);
241
242 while (1) {
243 writel(WDT_SWRST_KEY, addr: wdt_base + WDT_SWRST);
244 mdelay(5);
245 }
246
247 return 0;
248}
249
250static int mtk_wdt_ping(struct watchdog_device *wdt_dev)
251{
252 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd: wdt_dev);
253 void __iomem *wdt_base = mtk_wdt->wdt_base;
254
255 iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST);
256
257 return 0;
258}
259
260static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
261 unsigned int timeout)
262{
263 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd: wdt_dev);
264 void __iomem *wdt_base = mtk_wdt->wdt_base;
265 u32 reg;
266
267 wdt_dev->timeout = timeout;
268 /*
269 * In dual mode, irq will be triggered at timeout / 2
270 * the real timeout occurs at timeout
271 */
272 if (wdt_dev->pretimeout)
273 wdt_dev->pretimeout = timeout / 2;
274
275 /*
276 * One bit is the value of 512 ticks
277 * The clock has 32 KHz
278 */
279 reg = WDT_LENGTH_TIMEOUT((timeout - wdt_dev->pretimeout) << 6)
280 | WDT_LENGTH_KEY;
281 iowrite32(reg, wdt_base + WDT_LENGTH);
282
283 mtk_wdt_ping(wdt_dev);
284
285 return 0;
286}
287
288static void mtk_wdt_init(struct watchdog_device *wdt_dev)
289{
290 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd: wdt_dev);
291 void __iomem *wdt_base;
292
293 wdt_base = mtk_wdt->wdt_base;
294
295 if (readl(addr: wdt_base + WDT_MODE) & WDT_MODE_EN) {
296 set_bit(WDOG_HW_RUNNING, addr: &wdt_dev->status);
297 mtk_wdt_set_timeout(wdt_dev, timeout: wdt_dev->timeout);
298 }
299}
300
301static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
302{
303 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd: wdt_dev);
304 void __iomem *wdt_base = mtk_wdt->wdt_base;
305 u32 reg;
306
307 reg = readl(addr: wdt_base + WDT_MODE);
308 reg &= ~WDT_MODE_EN;
309 reg |= WDT_MODE_KEY;
310 iowrite32(reg, wdt_base + WDT_MODE);
311
312 return 0;
313}
314
315static int mtk_wdt_start(struct watchdog_device *wdt_dev)
316{
317 u32 reg;
318 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd: wdt_dev);
319 void __iomem *wdt_base = mtk_wdt->wdt_base;
320 int ret;
321
322 ret = mtk_wdt_set_timeout(wdt_dev, timeout: wdt_dev->timeout);
323 if (ret < 0)
324 return ret;
325
326 reg = ioread32(wdt_base + WDT_MODE);
327 if (wdt_dev->pretimeout)
328 reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
329 else
330 reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
331 if (mtk_wdt->disable_wdt_extrst)
332 reg &= ~WDT_MODE_EXRST_EN;
333 if (mtk_wdt->reset_by_toprgu)
334 reg |= WDT_MODE_CNT_SEL;
335 reg |= (WDT_MODE_EN | WDT_MODE_KEY);
336 iowrite32(reg, wdt_base + WDT_MODE);
337
338 return 0;
339}
340
341static int mtk_wdt_set_pretimeout(struct watchdog_device *wdd,
342 unsigned int timeout)
343{
344 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd);
345 void __iomem *wdt_base = mtk_wdt->wdt_base;
346 u32 reg = ioread32(wdt_base + WDT_MODE);
347
348 if (timeout && !wdd->pretimeout) {
349 wdd->pretimeout = wdd->timeout / 2;
350 reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
351 } else if (!timeout && wdd->pretimeout) {
352 wdd->pretimeout = 0;
353 reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
354 } else {
355 return 0;
356 }
357
358 reg |= WDT_MODE_KEY;
359 iowrite32(reg, wdt_base + WDT_MODE);
360
361 return mtk_wdt_set_timeout(wdt_dev: wdd, timeout: wdd->timeout);
362}
363
364static irqreturn_t mtk_wdt_isr(int irq, void *arg)
365{
366 struct watchdog_device *wdd = arg;
367
368 watchdog_notify_pretimeout(wdd);
369
370 return IRQ_HANDLED;
371}
372
373static const struct watchdog_info mtk_wdt_info = {
374 .identity = DRV_NAME,
375 .options = WDIOF_SETTIMEOUT |
376 WDIOF_KEEPALIVEPING |
377 WDIOF_MAGICCLOSE,
378};
379
380static const struct watchdog_info mtk_wdt_pt_info = {
381 .identity = DRV_NAME,
382 .options = WDIOF_SETTIMEOUT |
383 WDIOF_PRETIMEOUT |
384 WDIOF_KEEPALIVEPING |
385 WDIOF_MAGICCLOSE,
386};
387
388static const struct watchdog_ops mtk_wdt_ops = {
389 .owner = THIS_MODULE,
390 .start = mtk_wdt_start,
391 .stop = mtk_wdt_stop,
392 .ping = mtk_wdt_ping,
393 .set_timeout = mtk_wdt_set_timeout,
394 .set_pretimeout = mtk_wdt_set_pretimeout,
395 .restart = mtk_wdt_restart,
396};
397
398static int mtk_wdt_probe(struct platform_device *pdev)
399{
400 struct device *dev = &pdev->dev;
401 struct mtk_wdt_dev *mtk_wdt;
402 const struct mtk_wdt_data *wdt_data;
403 int err, irq;
404
405 mtk_wdt = devm_kzalloc(dev, size: sizeof(*mtk_wdt), GFP_KERNEL);
406 if (!mtk_wdt)
407 return -ENOMEM;
408
409 platform_set_drvdata(pdev, data: mtk_wdt);
410
411 mtk_wdt->wdt_base = devm_platform_ioremap_resource(pdev, index: 0);
412 if (IS_ERR(ptr: mtk_wdt->wdt_base))
413 return PTR_ERR(ptr: mtk_wdt->wdt_base);
414
415 irq = platform_get_irq_optional(pdev, 0);
416 if (irq > 0) {
417 err = devm_request_irq(dev: &pdev->dev, irq, handler: mtk_wdt_isr, irqflags: 0, devname: "wdt_bark",
418 dev_id: &mtk_wdt->wdt_dev);
419 if (err)
420 return err;
421
422 mtk_wdt->wdt_dev.info = &mtk_wdt_pt_info;
423 mtk_wdt->wdt_dev.pretimeout = WDT_MAX_TIMEOUT / 2;
424 } else {
425 if (irq == -EPROBE_DEFER)
426 return -EPROBE_DEFER;
427
428 mtk_wdt->wdt_dev.info = &mtk_wdt_info;
429 }
430
431 mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
432 mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
433 mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
434 mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
435 mtk_wdt->wdt_dev.parent = dev;
436
437 watchdog_init_timeout(wdd: &mtk_wdt->wdt_dev, timeout_parm: timeout, dev);
438 watchdog_set_nowayout(wdd: &mtk_wdt->wdt_dev, nowayout);
439 watchdog_set_restart_priority(wdd: &mtk_wdt->wdt_dev, priority: 128);
440
441 watchdog_set_drvdata(wdd: &mtk_wdt->wdt_dev, data: mtk_wdt);
442
443 mtk_wdt_init(wdt_dev: &mtk_wdt->wdt_dev);
444
445 watchdog_stop_on_reboot(wdd: &mtk_wdt->wdt_dev);
446 err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
447 if (unlikely(err))
448 return err;
449
450 dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
451 mtk_wdt->wdt_dev.timeout, nowayout);
452
453 wdt_data = of_device_get_match_data(dev);
454 if (wdt_data) {
455 err = toprgu_register_reset_controller(pdev,
456 rst_num: wdt_data->toprgu_sw_rst_num);
457 if (err)
458 return err;
459
460 mtk_wdt->has_swsysrst_en = wdt_data->has_swsysrst_en;
461 }
462
463 mtk_wdt->disable_wdt_extrst =
464 of_property_read_bool(np: dev->of_node, propname: "mediatek,disable-extrst");
465
466 mtk_wdt->reset_by_toprgu =
467 of_property_read_bool(np: dev->of_node, propname: "mediatek,reset-by-toprgu");
468
469 return 0;
470}
471
472static int mtk_wdt_suspend(struct device *dev)
473{
474 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);
475
476 if (watchdog_active(wdd: &mtk_wdt->wdt_dev))
477 mtk_wdt_stop(wdt_dev: &mtk_wdt->wdt_dev);
478
479 return 0;
480}
481
482static int mtk_wdt_resume(struct device *dev)
483{
484 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);
485
486 if (watchdog_active(wdd: &mtk_wdt->wdt_dev)) {
487 mtk_wdt_start(wdt_dev: &mtk_wdt->wdt_dev);
488 mtk_wdt_ping(wdt_dev: &mtk_wdt->wdt_dev);
489 }
490
491 return 0;
492}
493
494static const struct of_device_id mtk_wdt_dt_ids[] = {
495 { .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data },
496 { .compatible = "mediatek,mt6589-wdt" },
497 { .compatible = "mediatek,mt6735-wdt", .data = &mt6735_data },
498 { .compatible = "mediatek,mt6795-wdt", .data = &mt6795_data },
499 { .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data },
500 { .compatible = "mediatek,mt7988-wdt", .data = &mt7988_data },
501 { .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data },
502 { .compatible = "mediatek,mt8186-wdt", .data = &mt8186_data },
503 { .compatible = "mediatek,mt8188-wdt", .data = &mt8188_data },
504 { .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data },
505 { .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data },
506 { /* sentinel */ }
507};
508MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);
509
510static DEFINE_SIMPLE_DEV_PM_OPS(mtk_wdt_pm_ops,
511 mtk_wdt_suspend, mtk_wdt_resume);
512
513static struct platform_driver mtk_wdt_driver = {
514 .probe = mtk_wdt_probe,
515 .driver = {
516 .name = DRV_NAME,
517 .pm = pm_sleep_ptr(&mtk_wdt_pm_ops),
518 .of_match_table = mtk_wdt_dt_ids,
519 },
520};
521
522module_platform_driver(mtk_wdt_driver);
523
524module_param(timeout, uint, 0);
525MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
526
527module_param(nowayout, bool, 0);
528MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
529 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
530
531MODULE_LICENSE("GPL");
532MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>");
533MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
534MODULE_VERSION(DRV_VERSION);
535

source code of linux/drivers/watchdog/mtk_wdt.c